A modulator is a device that uses a modulation signal to modify a periodic waveform, called a carrier signal, to add information to the carrier signal. For example, a modulator may use an electrical current in a signal electrode to generate a radio frequency field, and the radio frequency field may modify the carrier signal to add information to the carrier signal. Modulators are sometimes used to convert an electrical signal into an optical signal in an optical network. In such a case, the modulation signal may be based on the electrical signal, and the optical signal may be used as the carrier signal.